Published on Mar 15, 2021

Video Transcript

[MUSIC PLAYING] JOHN WHYTE: Welcome, everyone. You're watching Coronavirus in Context. I'm Dr. John Whyte, the chief medical officer at WebMD. Would you be willing to purposely get infected with the coronavirus so we could study you over time? That's exactly what 100 people approximately are doing in the United Kingdom, the so-called challenge trials so to help explain this, I asked Dr. Peter Openshaw. He is the professor of Experimental Medicine at the Imperial College in London. Dr. Openshaw, thanks for joining.

PETER OPENSHAW: It's a pleasure.

JOHN WHYTE: What are these challenge trials and why are we doing them?

PETER OPENSHAW: Well, we've been doing experimental infections of human volunteers for many, many years here in the UK. It's something which-- there is actually quite a long tradition which goes back actually several centuries to the time when Jenner was developing the smallpox vaccine. In more recent times after the Second World War, it was a facility which was set up on Salisbury Plain-- actually funded by the Americans called the Harvard Hospital-- which was established in order to do experimental common cold infections with many viruses, including coronaviruses.

And so many of us who've grown up with that sort of history in the UK, we're familiar with the idea that you might go off and be infected with influenza at flu camp and so when we've--

JOHN WHYTE: Flu camp, I had not heard that.

PETER OPENSHAW: Yeah, it was called flu camp. And you could go and take a couple of weeks' holiday out on Salisbury Plain, have everything looked after and the chances of actually getting flu were quite low. A lot of people were in control groups and it became quite an established sort of way of getting a completely inexpensive holiday and actually to be paid to be infected with these viruses.

So when that closed in the 1980s, a number of universities started doing their own versions of this and again, that tradition has been continued so we've been infecting people with common cold viruses, the rhinoviruses, more recently influenza virus and a virus that I've worked on for about 30 years called respiratory syncytial virus.

JOHN WHYTE: But we have treatments for those conditions.

PETER OPENSHAW: Well, there are treatments for influenza. You can use oseltamivir and the old days, they used to use the adamantane drugs but it's become resistant to that.

JOHN WHYTE: But why do it for COVID-19?

PETER OPENSHAW: So there's so much that you can learn by these challenge studies. If you just wait for people to come naturally infected, you can only really study the disease in its later course. You can't study the early effects of infection. You can't really study the interval between inoculation of the virus and the development of symptoms and you also can't really establish what's the minimal dose that's needed in order to become infected because those are not controlled studies. They're studies which are just opportunist.

JOHN WHYTE: So you take these healthy volunteers and you intentionally infect them with COVID-19--


JOHN WHYTE: --and then you study them over time?

PETER OPENSHAW: Yes. So the most important thing is that these volunteers are selected because they're very, very low-risk of developing serious disease so they're aged 18 to 30. We rigorously exclude anyone with any pre-existing health condition. And we start with the very, very smallest dose that we think might possibly cause nasal colonization with the virus and then we use remdesivir, an antiviral drug, to terminate the infection before symptoms appear, we expect. So we're not really intending to cause disease. We're just intending to cause nasal colonization with the virus.

JOHN WHYTE: Some people will say this is unethical. That you're intentionally infecting someone with a virus that we do not yet have good treatments for and we have a vaccine to help prevent infection. Is it unethical?

PETER OPENSHAW: We don't believe it is and it's been through the most rigorous series of ethical considerations. The dossier that we've had to produce for the ethics committee is extremely extensive. We've gone over the literature on this virus which by know is actually one of the most intensively studied viruses known to mankind.

I mean, we do know an awful lot about the virus that we are now using to infect and as I said, we are going to be using the very, very smallest dose we can. We're not using one of the new variants which we have less information about. We are using virus which was circulating during last summer where we really do have an awful lot of information about exactly how it behaves.

JOHN WHYTE: And then to play devil's advocate-- if you say we already know a great deal about COVID-19, you're selecting a population that by definition is much healthier, is at less risk, what are we really going to learn from these trials?

PETER OPENSHAW: Well, what we can do is very, very careful comparisons of the effects of different vaccines on virus shedding and whether different doses, different vaccines, different regimes for example, or different antiviral drugs we can determine their efficacy with very small studies-- much smaller than you would be able to if you were to wait for the very large studies on thousands of people that you would need to do in order to observe natural disease, and that's especially true as we begin to drive down the rates of infection.

When we have much less virus circulating in the community, it becomes extraordinarily difficult or sometimes impossible to design clinical trials in order to test these vital, vital questions without doing human infection challenge.

JOHN WHYTE: Other than the UK, are these trials being conducted anywhere else around the world?

PETER OPENSHAW: We are the first country in the world to give ethical approval for these trials. They are being planned in a number of other countries. The Netherlands in particular is also a world leader in human infection challenge studies and they are certainly planning to do these studies, but they don't yet have ethical approval.

JOHN WHYTE: Well Dr. Openshaw, I want to thank you for giving us some insights into this concept of the challenge trials and why we need to do them to gain more information about COVID-19.


JOHN WHYTE: And if you have questions about coronavirus, drop us a line. You can email them to me at [email protected] as well as post on Facebook, Instagram, and Twitter. Thanks for watching.